惊爆！Java实现下载文件的6种超炫方式大
1. 使用urlconnection：通过创建urlconnection对象，设置相关参数，如请求方法、连接超时等，然后获取输入流读取文件内容，再通过输出流将文件内容写入到本地文件。示例代码如下：
```java
url url = new url("文件url");
urlconnection conn = url.openconnection();
inputstream in = conn.getinputstream();
fileoutputstream out = new fileoutputstream("本地文件名");
byte[] buffer = new byte[1024];
int length;
while ((length = in.read(buffer)) != -1) {
out.write(buffer, 0, length);
}
in.close();
out.close();
```
2. 使用httpurlconnection：继承自urlconnection，专门用于http协议的连接。它提供了更多的http相关方法和属性。例如：
```java
httpurlconnection httpconn = (httpurlconnection) url.openconnection();
httpconn.setrequestmethod("get");
httpconn.connect();
inputstream in = httpconn.getinputstream();
fileoutputstream out = new fileoutputstream("本地文件名");
// 后续读写操作同urlconnection
```
3. 使用apache httpclient：功能强大的http客户端库。可以方便地发送http请求并处理响应。示例：
```java
closeablehttpclient httpclient = httpclients.createdefault();
httpget httpget = new httpget("文件url");
closeablehttpresponse response = httpclient.execute(httpget);
httpentity entity = response.getentity();
inputstream in = entity.getcontent();
fileoutputstream out = new fileoutputstream("本地文件名");
// 后续读写操作
response.close();
httpclient.close();
```
4. 使用okhttp：简洁高效的http库。代码示例：
```java
okhttpclient client = new okhttpclient();
request request = new request.builder().url("文件url").build();
response response = client.newcall(request).execute();
responsebody body = response.body();
inputstream in = body.bytestream();
fileoutputstream out = new fileoutputstream("本地文件名");
// 后续读写操作
response.close();
```
5. 使用spring框架的resttemplate：用于在spring应用中进行restful服务调用。示例：
```java
resttemplate resttemplate = new resttemplate();
responseentity
byte[] body = response.getbody();
fileoutputstream out = new fileoutputstream("本地文件名");
out.write(body);
out.close();
```
6. 使用java nio：新的i/o api提供了更高效的文件操作。可以通过filechannel进行文件的读写。示例：
```java
path path = paths.get("本地文件名");
filechannel filechannel = filechannel.open(path, standardopenoption.write, standardopenoption.create);
url url = new url("文件url");
inputstream in = url.openstream();
filechannel.transferfrom(in, 0, long.max_value);
in.close();
filechannel.close();
```
